Re: Double Image Random Dot Stereograms

[P3D Andrew Woods <andrew@xxxxxxxxxxxxxxxxxxxxx>]

Harold R. Baize, Ph.D. <baize@xxxxxxxxxxxxx> wrote:
> Dr. T told me that all you need to do is copy a SIRDS twice and
> mount it with the correct displacement to produce the stereoscopic 
> image. It sounds like a wonderful idea to be able to copy 
> the same SIRDS in the left and right channels and project or view 
> them to produce a stereoscopic image. I will have to try that. 
> However, I'm sure that would produce lower resolution than a true 
> DIRDS, since each eye would also be viewing dots that contribute to the 
> image of the other half of the pair. 

It is not quite as simple to just repeat the first random image.
You need to repeat the first image but add parallax information.
It is the horizontal variation between the two images which 
determines the depth information.
What you are trying to do is very similar to the principle of converting
a 2D photograph into 3D.  Except in this case you are not trying
to add depth information to a conventional photograph but add
depth information to a random image.

I think Julesz's book "The Foundation of Cyclopean Perception"
makes a brief mention of how it is done.
 
> If anyone knows of an existing Intel/MS-DOS/Win program that can 
> generate DIRDSs I would be very grateful for the information.

No I don't know of such software, but depending upon how you
are viewing the images you may be able to use a SIRDS image.
Mount two copies of the SIRDS (one in front of each eye) 
but mount the second image one cycle of
the repeating pattern across relative to the other image.

Andrew.

 


------------------------------